Swab and surge effects can be caused when a tubular string (such as a drill string, casing string or completion string) is displaced in a wellbore. Such swab and surge effects can produce undesired pressure variations in the wellbore, possibly leading to fluid loss from the wellbore, influxes into the wellbore from a surrounding formation, fracturing of a formation, breakdown of a casing shoe, or other undesired consequences.
Therefore, it will be appreciated that improvements are continually needed in the art of mitigating swab and surge effects in wellbores.